Carburetor



P. S. TICE CARBURETOR Jul 5, 1932.

Original Filed Nov. 29, 1926 a shets-sneet 1 15a .23 DA JTLUBWI PerczUaZ 5 11a? P. s cE CARBURETOR Original FiledNov. 29, 1926 5 Sheets-Sheet 2 July 5, I I CARBURETOR Original Filed Nov. 29, 1926 3 Sheets-sheet 3 Vegjfoz .7

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i W wflzzo a Patented July 5, 1932 UNITED STATES PATENT OFFICE PERCIVAL S. TICE, OF CHICAGO, ILLINOIS, ASSIGNOR TO STEWART-WARNER CORPORA- TION, OF CHICAGO, ILLINOIS, A CORPCRATION OF VIRGINIA cannuanron Original application filed November 29, 1926, Serial No. 151,287. Divided and this application filed December 5, 1929. Serial No. 411,800.

This application is a division of my pending application Serial No. 151,287, filed November 29, 1926.

The purpose of the invention is to provide an improved construction in a carburetor for an internal combustion engine, for which purpose the invention consists in the elements and features of construction shown and described as defined in the claims.

In the drawings:

Figure 1 is a top plan view of a carburetor embodying this invention.

Figure 2 is asection at the line 22 on Figure 1.

Figure 3 is a section at the line 33 on Figure 2.

Figure 4 is a section at the line 44 on Figure 2.

Figure 5 is a section at the line 55 on Figure 2.

Figures 6, 7 and 8 are diagrammatic views of the nature of sections of the fuel mixture conduit and the entrance elbow thereto of several experimental forms by means of which the effective form for certain of the purposes of this invention has been developed.

Figure 9 is a section at the line 99 on Figure 4.

Figure 10 is a diagrammatic view for showing the fuel conduits and their inter-relat1onship. p

Referring to the drawings for specific description of the construction by which the purpose ofthe invention is accomplished:

ing therefore a posterior throttle.

The fuel element of the fuel mixture is derived from a fuel chamber shown as a level-governing chamber or float bowl 5, to which the fuel is supplied from a main o0 tank or like source, not shown, by gravity or other pressure through the inlet passage, 5, the admission of fuel 'to the fuel chamber, 5, being controlled by a float-operated valve, 6, the construction of the float and connections forsuch control being fully described and covered by my said parent application Serial No. 151,287, and requiring no description for the purpose of the present invention, which relates to other parts of the construction; and for the purposes of the invention to be covered in this application, it is only impor tant to note with respect to this float bowl and connections that the fuel flow fromthe fuel chamber to the mixing chamber of the carburetor ordinarily, that is, for main supply to the carburetor in the ordinary operation of the engine when running under load with wide open throttle, is by way of metering plug, 40.

This metering plug, 40, is inserted at the entrance to a short horizontal bore, 41, in a boss, 15, formed on the carburetor body, and thence up through a vertical bore, 42, in said boss to the intersection of said vertical bore with a horizontal bore, 42*, through which the fuel passes to an annular channel formed For engine idling, an auxiliary fuel pas:

sage is provided leading to a second annular channel formed by a second'groove, 50, encompassing the throat sleeve, 2, at a short distance above the groove, 43, to which channel, 50, the fuel is led from a restricted port, 46, opening from the fuel chamber into a vertical bore, 47 (see Fig. 2) leading up to a horizontal bore, 51, which discharges into said second groove, 50. The bore, 47, is formedby'drilling in from the top of the casting, and the bore is threaded at the upper part for receiving the threaded stem of a needle valve, 53, which seats at a port, 54, formed through a metering plug, 54, which is interposed in said passage, 47, said valve stem having a knob handle, 55, for manual adjustment of the valve to control, according to the judgment of the operator, the flow capacity of the auxiliary passage.

The knob-handle co-operates with a springpressed detent, 57, whose upper end engages counter-sinks, 55", in the under side of the knob handle to hold the valve yieldingly at the position at whichit may be set for regulating the flow of capacity of the port, 54". From the channel, 50, apertures, 58, are made opening into the fuel mixture conduit throat at opposite sides thereof and at positions ad-.

jacent to the ends of the bridge, 45.

Said auxiliary passage, 50, is rendered operative for furnishing an idlin fuel supply, by cooperation of a duct, 60, ormed in the wall of the fuel mixture conduit, 1, leading down from a port, 61, which is formed opening into the fuel mixture conduit beyond the seating position of the throttle, 3, and at its lower end communicating through a cross bore, 64, with said second or auxiliary chan nel, 50, said cross bore opening into the channel, 50, preferably directly opposite the discharge ports, 58.

The manner of functioning of this construction is that when the throttle valve is closed for idling of the engine, the relatively high vacuum resulting at the engine intake beyond the closed throttle, causes fuel to be sucked up through the auxiliary passage, 51, together with limited quantity of air drawn in through the ports, 58, affording a suitably rich mixture for idling.

Upon opening the throttle somewhat, from its idling position, the increased air flow through the throat, together with the actuation of the fuel, sup ly accelerating diaphragm, 93, hereinaf tier described, causes fuel discharge from the bridge ports 45.

Under condition of lesser throttle opening, the fuel thus delivered would accumulate on the bridge to a considerable depth before being earned away by the main air stream past the bridge; and the manner of its delivery would be irregular, were it not for the action of the air ports, 58, into which such fuel is drawn as Soon as it begins to accumulate on the bridge. The ports, 58, and associated passages leading to the beyond-throttle region pick up and deliver quickly, and in a relatively finely divided state, fuel delivered to the throat by the bridge ports, 45, whenever the depression across the ports, 58, is sufficient to cause flow into them from the throat.

Upon the throttle being opened fully for l M running at speed with load, the pressure at the ports, 58, and at the bridge ports, becom- 86 ing lower than that at the port, 61, all the fuel is fed into the air stream at said ports, 58 and 45.

Pressure-operated devices, including the diaphragm, 93, above referred to, for impelling auxiliary fuel supply for discharge into the fuel mixture conduit anterior to the throttle, which are shown in the drawings of this application, are fully shown, described and claimed in my vpending application Serial No. 136,251, filed September 18, 1926, and these parts and devices will be now briefly described introductory to certain detail description of the additions and modifications of these devices which will be pointed out as the description proceeds.

At each side, front and rear, of the carburetor at the neck of the casting which connects the body of the float bowl with the fuel mixture conduit, there is formed a diaphragm-partitioned chamber of which the cavity at one side of the partitioning diaphragm is formed by a recess in the face of the casting, and the cavity at the other side of the diaphragm is formed by a corresponding recess in the face of an applied cap, 91, the diaphragm-partition being clamped between the margins of the cavities as the cap is applied and bound in place by securing bolts.

In the drawings, (see Figure 4) the pair of partitioned cavities at the front side are seen respectively at 90 and 90 in the body casting, 92, andin the cap, 91,-partitioned from each other by the flexible diaphragm, 93. Corresponding cavities at the rear side of the body casting are seen at 110 in the body casting, and at 112 in the cap, 111, said cavities being partitioned from each other by the diaphragm, 113. A plunger, 96, having its stem, 95, mounted in the cap and pressed inwardly by a spring, 91*, tends to hold the diaphragm, 93, flexed inwardly for reducing the capacity of the cavity, 90.

The diaphragm, 113, partitioning this rear pair of cavities is bound, as to the main central part of its area, between the heads, 115 and 115", of two stems or plungers, 116 and 116*, the'former being spring-pressed outwardly by the spring, 117, and the latter being arranged to be thrust inwardly by one end of a lever, 150, which is pivoted at 151 on the cap, 111, and which is actuated at its opposite end by a cam, 152, on the protruding end of the throttle valve stem, 3.

A bore, 99, extending through the body casting, intersecting the bore, 42, puts the cavities, 90 and 110, in communication with the annular channel, 43, and with the duct, 44, and discharge apertures, 45*, of the bridge, 45, and thereby operates for discharge of fuel in the fuel mixture conduit anterior to the throttle.

The fuel reaches the cavity, 90, by way of ports, 120, leading to the inner end of the bore, 121, in which a hollow plunger, 122, having one end lodged against the diaphragm,

93, for action of the diaphragm on the plunger, 122, as hereinafter referred to, has its axial cavity communicating with the cavity, 90, by ports, 123, the entrance to said plunger cavity,the port, 124,-being controlled by a valve, 125, having a slender stem, 126, protruding through the port, 124,- toward which the valve is spring-pressed by a spring, 122 reacting between the inner end of the valve and an adjusting screw, 128, which is'set in the end of the plunger.

In the construction as thus far described, the valve, 125, would be always closed, preventing access of fuel to the cavity, 90, but for provision for causing said valve to be limitedly open to a degree variable by manual adjustment according to the requirements and judgment of the operator, said provision con sisting in a ball, 130, lodged at the entrance to the bore, 121, in which the'plunger, 122, reciprocates, but not obstructing fuel flow into said bore. ,8

Against this ball the stem, 126, of the valve, 125, is stopped, so that upon the inward flexure of the diaphragm, 93, the valve seat, 124, having the, port, is withdrawn from the valve, admitting flow of fuel into the cavity, 90. A cone-pointed adjusting stem, 135, set up through the under side of the body casting, has its cone point, 136, in positionfor encountering the ball, 130, at the side opposite the stem of the valve, 125, and adapted for screwing in or out to adjust the ball for positioning the valve, '125, so that the port, 124, shall be opened more or less widely at a given inward flexure of the diaphragm 90.

The fuel reaches the cavity, 110, by way of'the port, 132, whichis controlled by a check valve, 131, seating against return flow to the float bowl.

A duct, 140, is formed in the wall of the fuel mixture conduit parallel to the duct, 60, and about 90 degrees around from the latter, said duct, 140, being connected at its upper end by an oblique duct, 141, leading into the fuel mixture chamber beyond the seating position of the throttle valve.-

At its lower end, the duct, 140, is intersected by a horizontal duct, 142, opening out through the annular encompassing wall of the cavity, 90, registering with the duct 143, in the annular encompassin wall of the cavity, 92, in the cap, 91, which latter duct opens into said cavity, 92; and a thimble, 144. extending through the diaphragm, 93,

' at the marginal portion thereof at which it is clamped between the encompassing walls of the cavities, 90 and 92, respectively, bridges the junction of the two ducts, 142 and 143 at their registered ends.

This bridging of the junction of the two ducts, 142 and 143, at their registered ends,

ensures continuity of the pressure passage from the post-throttle region of the engine the fuel from thecavity, 90, y way of pas- I sages, 99 and 42 for discharge at the bridge apertures, 45".

For rendering substantially effective for its purpose, the construction shown, consisting in distribution of fuel ports along the bridge, 45, a corresponding distribution of the air flow so as to be substantially uniform over the entire cross section of the fuel mixture pipe throat, is necessary. I have ascertained by experiment that in the case of air driven or drawn,and particularly if drawn, as by suction,through a pipe elbow of uniform cross section throughout the bend, as in the diagrammatic view of Figure 6, or having uniformly diminishing,conical, cross section from entrance to discharge or connection with the fuel mixture conduit throat, as in the diagram Figure 7, the air current does not leave the elbow in lines parallel to the axis, but on the contrary, the air current tends toward the outer side of the elbow bend; and if such elbow in a carburetor connection is directly coupled with the fuel mixture throat, the current leans off toward the side opposite the intake of the elbow, as indicated by arrow lines, 200, in Figure 7.

I have found that it is not possible to correct or overcome this deflection so as to cause the current to enter the conduit throat in true axial direction as is necessary in order to distribute itself uniformly through the cross section of the throat, by giving the elbow a conical tapered terminal for connection with the throat as illustrated in Figure 6; but on the contrary with such connection the air stream is deflected to the opposite side of the elbow, as indicated by arrow lines, 201, in Figure 6.

. I have found that the desired result of uniform distribution of the air flow over the cross section of the throat with minimum eddying and internal turbulence in the air stream, is obtained by shaping the elbow to contract the cross sectional area as the discharge into the throat is approached, and

outer convex side of the bend with a radius less than required for contracting the passage uniformly. The result, as seen in Figure 8, is a well-rounded blending of the elbow section with the throat section, in which the curve, 202, shows the form of elbow of uniform cross section throughout, from which the actual outline deviates for contracting by curving with a radius less than would yield uniform contraction, as may be understood by comparing the successive radii, indicated at 203, in Figure 8, taken at equal angular intervals, the centerof the outer curve being offset in the plane of the junction of the elbow effecting this contraction by curving the 5, Figure 8.

I claim:

1. In a carburetor and the like for an internal combustion engine, in combination with a fuel mixture conduit comprising a throat through which the fuel mixture moves toward the engine intake, a fuel supply passage discharging in the conduit throat, said passage comprising a channel encompassing the throat, the conduit having a hollow bridge extending diametrically across the throat, the

cavity of the bridge communicating at both ends with said throat-encompassing channel, and having a plurality of ports distributed along the len th of the bridge for delivery of fuel onwar ly in the conduit.

2. In a carburetor, a fuel mixture conduit comprising a throat through which the fuel mixture moves toward the engine intake having at the throat a relatively narrow bridge extending across the throat-way, hollow from end to end, and a channel in the wall of the throat at the transverse plane at which the bridge is located adapted for. connection with a fuel supply passage, said channel communicating with the cavity of the hollow bridge, the bridge having a plurality of. fuel discharge ports leading from its cavity, distributed along its length for distributing the fuel discharge over the cross section of the throat.

3. In the construction defined in claim 2, the fuel mixture conduit having its throat formed by means of a sleeve fitting liquidtight in the conduit, the channel being formed as a groove in the outer surface of the sleeve encompassing the conduit, the conduit wall having a fuel duct which terminates in a port registering with said groove.

4. In a carburetor and the like for internal combustion engines, in combination with a fuel mixture conduit comprising a throat through which thetfuel mixture moves towards the engine intake, a fuel supply passage discharging in the conduit throat, the conduit having a hollow bridge extending dianietrically across the throat, said passage comprising a channel communicating with both ends of the cavity of the bridge and said bridge having a plurality of ports distributed along the length of the bridge for delivery of fuel onwardly in the conduit.

5. In a carburetor, a fuel mixture conduit forming a throat through which the fuel mixture is directed towards the fuel intake, a

hollow fuel feeding bridge extending diametrically across the throat, said bridge having a plurality of discharge ports distributed along the length thereof and a fuel supply passage including portions in communication with the opposite ends of said hollow bridge.

6. In a carburetor, a vertical fuel mixture conduit, a throat, an air intake elbow communicating at one end with said throat, a fuel supply passageway leading to the throat, a hollow bridge extending diametrically acrossthe throat perpendicular to the plane of the bend of the air intake elbow, said bridge having a plurality of discharge ports distributed along the length thereof, said fuel supply passage being in communication with the opposite ends of said hollow bridge, the air passage through said elbow being tapered narrowing throughout the bend, the outer curve having an approximate uniform radius about a center in the plane of the junction of the elbow with the straight portion of the throat and offset in that plane away from the axis of said straight portion past the center of curvature of the inner side of the elbow a distance equal to the difference in diameter of the outer and inner ends of the elbow due to the taper.

7. In a carburetor, a Vertical fuel mixture conduit, a throat, an air intake elbow communicating at one end with said throat, a fuel supply passageway leading to the throat,a hollow bridge extending diametrically across the throat perpendicular to the plane of the bend of the air intake elbow, said bridge having a plurality of discharge ports distributed along the length thereof, said fuel supply passage being in communication with the opposite ends of said hollow bridge, the air passage through said elbow being tapered narrowing throughout the bend of the elbow, .the outer curve of the elbow being so much offset from the center of the inner curve and with such a radius as to cause the elbow passage to taper-narrowing at an increasing rate from the outer end to a point in the outer curve at which a tangent thereto is parallel to the axis of the throat.

In testimon whereof I have hereunto set my hand at hicago, Illinois, this 29th day of November, 1929.

\ PERCIVAL S. TICE. 

